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Biomedical subjects

E Morris

Publications and source records attributed to E Morris.

At least 37 records · Page 2Linked to original sources
PubMed2001

A randomized comparison between rasburicase and allopurinol in children with lymphoma or leukemia at high risk for tumor lysis.

Standard therapy in the United States for malignancy-associated hyperuricemia consists of hydration, alkalinization, and allopurinol. Urate oxidase catalyzes the enzymatic oxidation of uric acid to a 5 times increased urine soluble product, allantoin. Rasburicase is a new recombinant form of urate oxidase available for clinical evaluation. This multicenter randomized trial compared allopurinol to rasburicase in pediatric patients with leukemia or lymphoma at high risk for tumor lysis. Patients received the assigned uric acid-lowering agent for 5 to 7 days during induction chemotherapy. The primary efficacy end point was to compare the area under the serial plasma uric acid concentration curves during the first 96 hours of therapy (AUC(0-96)). Fifty-two patients were randomized at 6 sites. In an intent-to-treat analysis, the mean uric acid AUC(0-96) was 128 +/- 70 mg/dL.hour for the rasburicase group and 329 +/- 129 mg/dL.hour for the allopurinol group (P <.0001). The rasburicase versus allopurinol group experienced a 2.6-fold (95% CI: 2.0-3.4) less exposure to uric acid. Four hours after the first dose, patients randomized to rasburicase compared to allopurinol achieved an 86% versus 12% reduction (P <.0001) of initial plasma uric acid levels. No antirasburicase antibodies were detected at day 14. This randomized study demonstrated more rapid control and lower levels of plasma uric acid in patients at high risk for tumor lysis who received rasburicase compared to allopurinol. For pediatric patients with advanced stage lymphoma or high tumor burden leukemia, rasburicase is a safe and effective alternative to allopurinol during initial chemotherapy.

Adolescent↗
PubMed2001

Comparison of tibial plateau angles in dogs with and without cranial cruciate ligament injuries.

OBJECTIVE: To measure and compare tibial plateau angles (TPA) of dogs with cranial cruciate ligament (CrCL) injuries and dogs without CrCL injuries. DESIGN: Prospective study. ANIMALS: 87 dogs. PROCEDURE: Stifle joints were measured from lateral radiographic views to determine TPA in 3 groups: group-1 dogs had CrCL injuries, group-1a dogs, a subgroup of group 1, had 1 unaffected stifle joint, and group-2 dogs had no CrCL injuries. Age, sex, breed, body weight, limb injured, and TPA were recorded for each dog. RESULTS: 56 stifle joints were measured in group-1 dogs; mean TPA was 23.76 degrees , and mean age and weight were 5.7 years and 37.91 kg (83.4 lb), respectively. Fourteen stifle joints were measured in group-1a dogs; mean TPA was 24.71 degrees , and mean age and weight were 5.6 years and 38.06 kg (83.8 lb), respectively. Sixty stifle joints were measured in group-2 dogs; mean TPA was 18.10 degrees , and mean age and weight of these dogs were 4.83 years and 35.85 kg (79 lb), respectively. The most common breeds included Labrador Retriever, Golden Retriever, and Rottweiler. The TPA of dogs in group 1 and group 1a were significantly greater than the TPA of dogs in group 2. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs with CrCL injuries have a significantly greater TPA than dogs without CrCL injury. With further investigation, a normal TPA can be determined. In the future, TPA measurements may be used to screen dogs suspected of being susceptible to CrCL injury.

Animals↗
PubMed2001

Three-dimensional structure of the photosystem II core dimer of higher plants determined by electron microscopy.

Here we report the first three-dimensional structure of a higher plant photosystem II core dimer determined by electron crystallography at a resolution sufficient to assign the organization of its transmembrane helices. The locations of 34 transmembrane helices in each half of the dimer have been deduced, 22 of which are assigned to the major subunits D1 (5), D2 (5), CP47 (6), and CP43 (6). CP47 and CP43, located on opposite sides of the D1/D2 heterodimer, are structurally similar to each other, consisting of 3 pairs of transmembrane helices arranged in a ring. Both CP47 and CP43 have densities protruding from the lumenal surface, which are assigned to the loops joining helices 5 and 6 of each protein. The remaining 12 helices within each half of the dimer are attributed to low-molecular-weight proteins having single transmembrane helices. Comparison of the subunit organization of the higher plant photosystem II core dimer reported here with that of its thermophilic cyanobacterial counterpart recently determined by X-ray crystallography shows significant similarities, indicative of a common evolutionary origin. Some differences are, however, observed, and these may relate to variations between the two classes of organisms in antenna linkage or thermostability.

Dimerization↗
PubMed2001

Superoxide dismutase and catalase do not affect the pulmonary hypertensive response to group B streptococcus in the lamb.

The purpose of this study was to determine whether treatment with conjugated antioxidant enzymes could attenuate or abolish pulmonary hypertension induced by group B streptococcus (GBS). Lambs, 3-7 d old, were anesthetized and ventilated. Intravascular catheters were placed in the left ventricle, descending aorta, right atrium, and pulmonary artery for continuous monitoring of intravascular pressures. Cardiac output was measured with radiolabeled microspheres. Measurements were obtained at baseline and 15 and 60 min into a 60-min GBS infusion, and 60 min after GBS was stopped. Blood gas values were held constant and PaO(2) was maintained >100 mm Hg. The control group received saline vehicle only (n = 6), the GBS group received GBS infusion only (n = 9), the enzymes (ENZ) group received polyethylene glycol-superoxide dismutase (PEG-SOD) and polyethylene glycol-catalase (PEG-CAT) treatment only (n = 6), and the ENZ+GBS group received PEG-SOD and PEG-CAT then GBS (n = 9). Plasma samples were obtained to confirm increased superoxide dismutase and catalase activities in the groups receiving enzymes. Compared with baseline, pulmonary vascular resistance increased by 119% and 101% at 15 min and 87% and 81% at 60 min in the GBS and ENZ+GBS groups, respectively. Sixty minutes after the termination of the GBS infusion, PVR returned to baseline in the GBS group but did not in the ENZ+GBS group. Enzyme infusions resulted in at least a ninefold increase in plasma enzyme activities. As opposed to previously published data from endotoxin models, PEG-CAT and PEG-SOD were ineffective in altering the GBS-induced pulmonary hypertensive response in this model. This suggests that acute administration of antioxidant enzymes may not be effective in ameliorating GBS-induced pulmonary hypertension.

Animals↗
PubMed2000

Revealing the structure of the photosystem II chlorophyll binding proteins, CP43 and CP47.

A review of the structural properties of the photosystem II chlorophyll binding proteins, CP47 and CP43, is given and a model of the transmembrane helical domains of CP47 has been constructed. The model is based on (i) the amino acid sequence of the spinach protein, (ii) an 8 A three-dimensional electron density map derived from electron crystallography and (iii) the structural homology which the membrane spanning region of CP47 shares with the six N-terminal transmembrane helices of the PsaA/PsaB proteins of photosystem I. Particular emphasis has been placed on the position of chlorophyll molecules assigned in the 8 A three-dimensional map of CP47 (K.-H. Rhee, E.P. Morris, J. Barber, W. Kühlbrandt, Nature 396 (1998) 283-286) relative to histidine residues located in the transmembrane regions of this protein which are likely to form axial ligands for chlorophyll binding. Of the 14 densities assigned to chlorophyll, the model predicted that five have their magnesium ions within 4 A of the imidazole nitrogens of histidine residues. For the remaining seven histidine residues the densities attributed to chlorophylls were within 4-8 A of the imidazole nitrogens and thus too far apart for direct ligation with the magnesium ion within the tetrapyrrole head group. Improved structural resolution and reconsiderations of the orientation of the porphyrin rings will allow further refinement of the model.

Amino Acid Sequence↗
PubMed2000

Phosphatidylglycerol is involved in the dimerization of photosystem II.

Photosystem II core dimers (450 kDa) and monomers (230 kDa) consisting of CP47, CP43, the D1 and D2 proteins, the extrinsic 33-kDa subunit, and the low molecular weight polypeptides PsbE, PsbF, PsbH, PsbI, PsbK, PsbL, PsbTc, and PsbW were isolated by sucrose density gradient centrifugation. The photosystem II core dimers were treated with phospholipase A2 (PL-A2), which cuts phosphatidylglycerol (PG) and phosphatidylcholine molecules at the sn-2 position. The PL-A2-treated dimers dissociated into two core monomers and further, yielding a CP47-D1-D2 subcomplex and CP43. Thin layer chromatography showed that photosystem II dimers contained four times more PG than their monomeric counterparts but with similar levels of phosphatidylcholine. Consistent with this was the finding that, compared with monomers, the dimers contained a higher level of trans-hexadecanoic fatty acid (C16:1Delta3tr), which is specific to PG of the thylakoid membrane. Moreover, treatment of dimers with PL-A2 increased the free level of this fatty acid specific to PG compared with untreated dimers. Further evidence that PG is involved in stabilizing the dimeric state of photosystem II comes from reconstitution experiments. Using size exclusion chromatography, it was shown that PG containing C16:1Delta3tr, but not other lipid classes, induced significant dimerization of isolated photosystem II monomers. Moreover, this dimerization was observed by electron crystallography when monomers were reconstituted into thylakoid lipids containing PG. The unit cell parameters, p2 symmetry axis, and projection map of the reconstituted dimer was similar to that observed for two-dimensional crystals of the native dimer.

Chromatography, High Pressure Liquid↗
PubMed2000

Crystallisation of CP43, a chlorophyll binding protein of photosystem II: an electron microscopy analysis of molecular packing.

Microcrystals of the chlorophyll binding protein, CP43, isolated from spinach thylakoid membranes have been studied by electron microscopy both in negative stain and in vitreous ice. Image analyses of three characteristic views show that the crystals are built of five different layers perpendicular to the c-axis. Each layer consists of different orientations of the CP43 protein. The unit cell derived from the end-on view (looking down the c-axis) shows an angle of 120 degrees, suggesting a threefold rotational symmetry. Both negative staining and cryo data are consistent with a hexagonal crystal lattice. Interpretation of the arrangement of the CP43 protein within this crystal lattice can be made based on 8- and 9-A electron crystallographic structures previously published that provide a model for the organisation of the transmembrane helices of CP43. Overall the analysis presented is consistent with X-ray diffraction data obtained from larger CP43 crystals and forms a framework on which to base further structural studies of this chlorophyll binding protein.

Crystallization↗
PubMed2000

Distinctive patterns of memory function in subgroups of females with Turner syndrome: evidence for imprinted loci on the X-chromosome affecting neurodevelopment.

X-monosomy is a form of Turner syndrome (TS) in which an entire X chromosome is missing. It is usually assumed that neuropsychological deficits in females with TS result from insufficient dosage of gene products from alleles on the sex chromosomes. If so, then parental origin of the single X chromosome should be immaterial. However, if there are imprinted genes on the X chromosome affecting brain development, neuropsychological development will depend on the parental origin of the single X chromosome. We contrasted verbal and visuospatial memory in females with a single paternal X chromosome (45,X(p)) and those with a single maternal X (45,X(m)). Neither group showed any impairment on immediate story recall; if anything, performance was above control levels. Groups did not differ on a measure of delayed recall. However, when delayed recall was considered after adjusting for level of immediate recall, 45,X(m) females showed enhanced verbal forgetting relative to controls over a delay. On the Rey figure, both groups were poor at copying the figure, but, after adjusting scores for initial copy score and strategy, only the 45,X(p) females showed disproportionate forgetting relative to controls. We propose there may be one or more imprinted genes on the X chromosome that affect the development of lateralised brain regions important for memory function.

Adolescent↗
PubMed2000

Combination hydrocodone and ibuprofen versus combination oxycodone and acetaminophen in the treatment of postoperative obstetric or gynecologic pain.

OBJECTIVE: The objective of this study was to compare the effectiveness of combination hydrocodone and ibuprofen with that of combination oxycodone and acetaminophen in the treatment of moderate to severe postoperative obstetric or gynecologic pain. BACKGROUND: Hydrocodone 7.5 mg with ibuprofen 200 mg is the only approved fixed-dose combination analgesic containing an opioid and ibuprofen. METHODS: This randomized, double-blind, parallel-group, single-dose, active-comparator, placebo-controlled study compared the effects of a 2-tablet dose of hydrocodone 7.5 mg and ibuprofen 200 mg with those of a 2-tablet dose of oxycodone 5 mg and acetaminophen 325 mg and placebo. Analgesia was assessed over 8 hours. RESULTS: Mean pain relief (PR) scores were similar for the hydrocodone with ibuprofen and oxycodone with acetaminophen groups (n = 61 and 59, respectively) at 0.5, 1, 1.5, 2, 2.5, 3, 4, and 7 hours and significantly greater for the hydrocodone with ibuprofen group at 5, 6, and 8 hours (P < or = 0.05). Mean pain intensity difference (PID) scores were similar for hydrocodone with ibuprofen and oxycodone with acetaminophen at 0.5, 1, 1.5, 2, 2.5, 3, and 4 hours and significantly greater for hydrocodone with ibuprofen at 5, 6, 7, and 8 hours (P < or = 0.05). Total PR scores were similar for hydrocodone with ibuprofen and oxycodone with acetaminophen for the 0- to 3- and 0- to 4-hour intervals and significantly greater for hydrocodone with ibuprofen for the 0- to 6- and 0- to 8-hour intervals (P < 0.05). The sum of the PID scores was similar for hydrocodone with ibuprofen and oxycodone with acetaminophen for the 0- to 3-, 0- to 4-, 0- to 6-, and 0- to 8-hour intervals. The median estimated time to onset of analgesia, mean peak PR score, median time to remedication, and mean global assessment score were similar for hydrocodone with ibuprofen and oxycodone with acetaminophen. Assay sensitivity was demonstrated by the presence of statistically significant differences between both active treatments and placebo (n = 60). The number of patients experiencing adverse events was similar for each of the 3 groups (11 [18.0%], hydrocodone with ibuprofen; 7 [11.9%], oxycodone with acetaminophen; and 6 [10.0%], placebo). CONCLUSIONS: In this study, a 2-tablet dose of combination hydrocodone 7.5 mg and ibuprofen 200 mg was as effective as a 2-tablet dose of combination oxycodone 5 mg and acetaminophen 325 mg in the treatment of moderate to severe postoperative obstetric or gynecologic pain. Both treatments were superior to placebo. The results of this study suggest that the combination of hydrocodone 7.5 mg and ibuprofen 200 mg may offer prescribers an additional option in combination pain therapy.

Acetaminophen↗
PubMed2000

Combination hydrocodone and ibuprofen versus combination codeine and acetaminophen for the treatment of chronic pain.

OBJECTIVE: The objective of this study was to compare the effectiveness of combination hydrocodone 7.5 mg and ibuprofen 200 mg with that of combination codeine 30 mg and acetaminophen 300 mg for the treatment of chronic pain. BACKGROUND: Hydrocodone 7.5 mg with ibuprofen 200 mg is the only approved fixed-dose combination analgesic containing an opioid and ibuprofen. METHODS: In this randomized, parallel-group, double-blind, repeated-dose, active-comparator, 4-week, multicenter study, 469 patients were randomly assigned to receive a 1-tablet (n = 156) or 2-tablet (n = 153) dose of combination hydrocodone 7.5 mg and ibuprofen 200 mg (HI1 and HI2, respectively) or a 2-tablet dose of combination codeine 30 mg and acetaminophen 300 mg (CA, n = 160), the active comparator, every 6 to 8 hours as needed for pain. Efficacy was measured through pain relief scores, number of daily doses of study medication, number of daily doses of supplemental analgesics, number of patients who discontinued therapy due to an unsatisfactory analgesic response, and global assessment scores. RESULTS: Of the 469 patients, 255 (54.4%) were female and 214 (45.6%) were male. The mean age was 51.1 years. Types of chronic pain included back (214; 45.6%), arthritic (145; 30.9%), other musculoskeletal (65; 13.9%), cancer (6; 1.3%), diabetic neuropathic (3; 0.6%), postherpetic neuralgic (5; 1.1%), other neurologic (21; 4.5%), and other unclassified chronic pain (10; 2.1%). During the 48 hours prior to the study, 351 (74.8%) patients had been treated with opioid or opioid-nonopioid combination analgesics. The overall mean daily pain relief score was significantly greater in the HI2 group (2.25+/-0.89) than in the HI1 group (1.98+/-0.87) (P = 0.003) or the CA group (1.85+/-0.96) (P < 0.001). The overall mean number of daily doses of study medication was significantly less in the HI2 group (2.94+/-0.99) than in the HI1 group (3.23+/-0.76) (P = 0.036) or the CA group (3.26+/-0.75) (P = 0.014). The overall mean number of daily doses of supplemental analgesics was significantly less in the HI2 group (0.24+/-0.49) than in the HI1 group (0.34+/-0.58) (P = 0.021) or CA group (0.49+/-0.85) (P = 0.010). The number of patients who discontinued treatment due to an unsatisfactory analgesic response was significantly less in the HI2 group (2; 1.3%) than in the CA group (12; 7.5%) (P = 0.008). HI2 was more effective than HI1 and CA as measured by pain relief scores for week 1 (P < 0.001 vs HI1 and CA), week 2 (P < 0.001 vs HI1 and CA), and week 3 (P = 0.008 vs HI1 and P < 0.001 vs CA); daily doses of study medication for week 1 (P = 0.019 vs HI1 and P = 0.011 vs CA); daily doses of supplemental analgesics for week 1 (P = 0.010 vs HI1 and CA); and global assessment scores for week 1 (P = 0.018 vs HI1 and P < 0.001 vs CA), week 2 (P = 0.005 vs HI1 and P < 0.001 vs CA), and week 4 (P = 0.013 vs HI1 and P = 0.023 vs CA). There were no significant differences between HI1 and CA in any efficacy variable. There were no significant differences in the number of patients experiencing adverse events in the HI2 (127; 83%), HI1 (124; 79.5%), and CA (129; 80.6%) groups. However, the mean number of patients who discontinued treatment due to adverse events was significantly greater in the HI2 group (40; 26.1%) than in the HI1 group (23; 14.7%) (P = 0.013). CONCLUSIONS: The results of this study suggest that 2-tablet doses of combination hydrocodone 7.5 mg and ibuprofen 200 mg may be more effective than either 1-tablet doses of this combination or 2-tablet doses of combination codeine 30 mg and acetaminophen 300 mg. Moreover, 1-tablet doses of combination hydrocodone 7.5 mg and ibuprofen 200 mg may be as effective as 2-tablet doses of combination codeine 30 mg and acetaminophen 300 mg.

Acetaminophen↗
PubMed2000

Dose-response effect of combination hydrocodone with ibuprofen in patients with moderate to severe postoperative pain.

OBJECTIVE: The objective of this study was to demonstrate a dose-response effect with 1- and 2-tablet doses of combination hydrocodone 7.5 mg with ibuprofen 200 mg and placebo in patients with moderate to severe postoperative abdominal or gynecologic pain. BACKGROUND: Hydrocodone 7.5 mg with ibuprofen 200 mg is the only approved fixed-dose combination analgesic containing an opioid and ibuprofen. Previous studies with this combination have demonstrated that the components have an additive analgesic effect as well as efficacy compared with other fixed-dose combination analgesics. METHODS: This randomized, parallel-group, double-blind, single-dose, placebo-controlled study compared 1 tablet of hydrocodone 7.5 mg with ibuprofen 200 mg (n = 60), 2 tablets of hydrocodone 7.5 mg with ibuprofen 200 mg (n = 60), and placebo (n = 60) in patients with moderate or severe pain after abdominal or gynecologic surgery. Analgesia was evaluated over 8 hours. RESULTS: Mean pain relief (PR) scores were significantly greater for the 2-tablet dose than for the 1-tablet dose at 80 (P = 0.027) and 100 (P = 0.017) minutes and at 2 (P = 0.013), 2.5 (P = 0.012), 3 (P = 0.006), 4 (P = 0.029), 5 (P = 0.002), 6 (P = 0.032), 7 (P = 0.036), and 8 (P = 0.01) hours. Mean pain intensity difference scores were significantly greater for the 2-tablet dose than for the 1-tablet dose at 80 (P = 0.013) and 100 (P = 0.007) minutes and at 2 (P = 0.003), 2.5 (P = 0.002), 3 (P = 0.002), 4 (P = 0.009), 5 (P < 0.001), 6 (P = 0.004), 7 (P = 0.009), and 8 (P = 0.001) hours. Mean total PR scores were significantly greater for the 2-tablet dose than for the 1-tablet dose for all measured time intervals (0 to 3 hours, P = 0.01; 0 to 4 hours, P = 0.006; 0 to 6 hours, P = 0.003; 0 to 8 hours, P = 0.003). Mean sum of pain intensity differences was significantly greater for the 2-tablet dose than for the 1-tablet dose for all measured time intervals (0 to 3 hours, P = 0.004; 0 to 4 hours, P < 0.001; 0 to 6 hours, P < 0.001; 0 to 8 hours, P < 0.001). Mean peak PR score and median time-to-remedication were significantly greater for the 2-tablet dose than for the 1-tablet dose (P < 0.029 and P = 0.017, respectively). Both doses were superior to placebo. There were no significant differences in the number of patients experiencing adverse events between the 2-tablet dose (n = 6 [10.0%]), the 1-tablet dose (n = 4 [6.7%]), and placebo (n = 1 11.7%]). Adverse events were not serious, and none of the patients discontinued therapy because of side effects. CONCLUSIONS: This study demonstrated that a 2-tablet dose of hydrocodone with ibuprofen provided significantly more analgesia than a 1-tablet dose (a positive dose-response effect) and that both doses were superior to placebo.

Dose-Response Relationship, Drug↗
PubMed2000

Ring-X chromosomes: their cognitive and behavioural phenotype.

We tested the cognitive abilities and educational attainments of 47 patients with a ring X chromosome, to evaluate the extent to which these variables correlated with failure of r(X) inactivation and with mosaicism. We found possession of a r(X) chromosome was associated with an increased risk of significant learning difficulties, and with associated behavioural maladjustment, compared with 45,X Turner females. Nearly a third had been educated outside mainstream schools. The proportion of cells in peripheral blood containing an inactivated r(X) chromosome was negatively correlated with nonverbal IQ. The parental origin of the normal chromosome did not appear to affect adjustment or abilities. In a minority of r(X) cases associated with mental retardation, there had been a failure to inactivate the ring, due to loss of the XIST locus. However, failure of X-inactivation was not necessarily associated with a severe phenotype. The degree of impairment in IQ depended on the size of the active ring, and hence was proportionate to the number of (as yet unidentified) genes whose functional disomy affected brain development and functioning.

Adolescent↗
PubMed2000

Severe digital necrosis in an elderly patient with heterozygous factor V Leiden mutation.

We report an 81-year-old female with a heterozygous factor V Leiden mutation who developed purpura fulminans. Digital necrosis, a characteristic clinical feature of purpura fulminans was prominent. Purpura fulminans is more common in children and adult cases are rare. Of eight reported cases of purpura fulminans resulting from a heterozygous factor V Leiden mutation recorded in the literature, only two were in adults: 40 and 42 years of age, respectively. This is the first report of this condition arising in a patient in her eighties.

Aged↗
PubMed2000

Prosthesis cost containment in total joint replacement: a physician-driven free-market approach.

As an alternative to a limited vendor/volume discount approach, our hospital employed a physician-driven free market strategy aimed at reducing joint implant costs. Surgeons were provided with vendor pricing and peer profile comparisons of implant cost data and asked to select implants providing the best value based on patient need. Vendors were challenged to reduce prices where appropriate. Total savings based on the 1995-1997 volume-adjusted cost difference were $1,059,159, a 17.5% decrease. These results demonstrate the possibility of reducing joint implant costs using a strategy that does not limit vendors or cap prices.

Arthroplasty, Replacement↗